Starting with systemd-236, the sysv-utils USE flag is enabled by
default.
The sysv-utils USE flag controls installation of symlinks for several
key commands:
/sbin/halt -> ../bin/systemctl
/sbin/init -> ../lib/systemd/systemd
/sbin/reboot -> ../bin/systemctl
/sbin/poweroff -> ../bin/systemctl
/sbin/runlevel -> ../bin/systemctl
/sbin/shutdown -> ../bin/systemctl
/sbin/telinit -> ../bin/systemctl
These commands are otherwise provided by sys-apps/sysvinit. This package
is blocked by systemd when the sysv-utils USE flag is enabled.
Enabling sysv-utils should cause Portage to un-merge sysvinit and OpenRC
if they are currently installed. emerge may emit a warning message
before doing so; if you are booting with systemd, this message is safe
to ignore.
If you wish to keep sysvinit (and openrc) installed, you may disable the
sysv-utils USE flag locally.
If you run into unresolvable blockers with sysv-utils enabled, ensure
that you do not have any reverse dependencies of sys-apps/sysvinit
selected (in your world file).
Common packages to look for:
sys-apps/sysvinit
sys-apps/openrc
net-misc/netifrc
The equery command from gentoolkit may help track down installed
packages that depend on openrc.
equery depends sys-apps/openrc